It is not the nose, it is the brain

Scents have the power to transform atmospheres, modulate behaviors, and can seduce, comfort, or heal. The sense of smell is the mirror of a society and also a historical portrait. This is stated by Dr. in neurosciences and research professor at CSIC, Laura López-Mascaraque, in her book El fascinante universo del olfato, published by geoPlaneta. A volume that aims to highlight the sense of smell, probably the greatly forgotten one, as priority has always been given to what we see and hear, when, in reality, smell is the gateway to memory and emotions and a way to explore the world.

As the author points out, "smell is a very invisible sense, but every time we breathe we are smelling, even when we are asleep. When we do this, we are interacting with the chemical world around us, and this often transforms our emotions or transforms our way of being. Evolutionarily, smell is the oldest sense of all and is directly connected to the part of the brain we call the emotional brain, the limbic system. Here, it processes information without filters, and this causes a scent to remind you of an episode associated with that scent." A sense that for many years has been culturally belittled, even though, on the contrary, there is an extensive vocabulary related to it – aroma, effluvium, essence, fragrance, stench, perfume, pestilence, reek, etc. – and that, even, in some cultures there are specific words to refer to certain smells, which does not happen here, beyond, perhaps, petrichor, the aroma that the earth gives off when it has rained.

Each person experiences smells differently, as we are talking about a profoundly individual sense. As the neuroscientist explains, "each one of us has what we call a unique olfactory register. Why? Because smell is controlled by almost 400 genes. What does this mean? That the genetic variability that each of us has in relation to smell is very large. Let's look at coriander, for example. You either love it or you can't stand it. And this is due to a gene, which we already know which one it is, that makes you perceive this smell in a certain way."

Laura López-Mascaraque remarks the importance of learning to live with a keen sense of smell and congratulates herself that current neuroscience is ending the contempt for this sense, since, according to the professor, losing the sense of smell is like living life in black and white. In this regard, she laments that we do not cultivate or understand the sense of smell, and that is why the book approaches it from multiple angles: biology, emotions, health, gastronomy, culture... She maintains that it is the bridge sense between the body and the world and that it also acts as a guardian, as it alerts us to the dangers that surround us, such as when we detect the smell of smoke or gas. Without forgetting the importance of smell in human relationships, since shared smells create belonging. Does the phrase "I have chemistry with this person" sound familiar? Well, it is actually smell, which is also fundamental in reproductive matters.Does this person have chemistry with me? Well, it is actually smell, which is also fundamental in reproductive matters.

And how can the sense of smell be trained? "By smelling. Just above our nose we have the only neurons in the brain that are in contact with the outside and are regenerating every 40 to 60 days. Unlike other senses, which we lose with age, we can continue to train and maintain our sense of smell throughout life. We can do this by creating a set of aromas, for example, by adding some spices, lemon, orange, some aromatic herb, some flowers, a perfume... and, from there, smelling, stimulating the receptors to function and transmit information to the brain," she says.

From health to gastronomy

Art, marketing, cooking, health, practically all areas of our lives have a connection with the sense of smell. The nose is essential for enjoying a meal, as without smell there is no pleasure (and if not, just ask those who lost their sense of smell as a consequence of covid), hence the impetus for what is known as neurogastronomy. Smells also play their part in art, literature, and cinema, appealing once again to the concept of emotional memory. They are an essential part of the world of perfumery and cosmetics, fields that have evolved significantly, but where the primitive idea that smelling good is a form of harmony with the world is maintained, where perfumes make us dream, awaken memories, and seal personalities. This is also explored in areas such as marketing, with what is known as olfactory marketing, in which smell is used as a market strategy to appeal to customers' emotions.

López-Mascaraque, who leads a group at the Cajal Neurosciences Center dedicated to the study of brain development, also highlights the link with medicine and health, recalling that bad smells have always been signals of danger, corruption, or disease. "In the Middle Ages, many diseases were detected by smell. There were urine wheels, and depending on the color and smell of the sample, or even the taste, it was determined what disease it was. Surely many remember, as children, hearing their mother or grandmother ask them to blow on their breath, to see if they were sick. And today we find, for example, trained dogs that can smell a lot of diseases and detect them effectively. If scientists delved deeper into this area, we could avoid many more invasive tests," she explains.

For all these reasons, Laura López-Mascaraque hopes that her book will serve to encourage us to smell more and to "do so consciously. It is also important to remember that if you lose your sense of smell, it can and should be recovered. And remember to teach children to smell. As soon as they start growing up, we teach them colors, letters, but nothing related to smell, and that cannot be. Let's play with smells, link them to stories, they will love it".